1. Field of the Invention
This invention relates to a component, an apparatus, and a method for analyzing molecules, and more particularly to a component, an apparatus, and a method for detecting emission signals from target molecules.
2. Description of the Prior Art
A method for detecting chemical interactions between two materials has been conventionally used representatively to determine whether DNA hybridization has occurred. For example, a plurality of probe molecules are provided on a substrate for possible reactions with sample molecules carrying binding partners. The sample molecules are fluorescently or electrochemically labeled. It is possible to estimate presence or degree of interactions between each probe molecule and each sample molecule by detecting emission signals from labeled molecules. The substrate including those target molecules may be referred to as a chip or an array.
In FIG. 6, there is shown a light detecting apparatus 37 employed in such a conventional method. The apparatus 37 includes a substrate 49 on which a plurality of samples 38 are arranged, an object lens 42, a beam splitter 43, a mirror 44, an emission filter 45, a light receiving lens 46, a focus pinhole 47, and a light receiver 48. Excitation beams 40 projected by an excitation beam generator (not shown) are reflected by the beam splitter 43 and directed to a sample 38. The sample 38 excited by the beam emits emission signals 41. Emission signals 41 are received by the object lens 42 which is disposed over the sample 38, passed through the beam splitter 43, lead to the emission filter 45 by way of the mirror 44, gathered by the light receiving lens 46, eliminated of noise signals by the focus pinhole 47, and detected by the light receiver 48.
When electrochemically labeled materials are included in the sample 38, the excitation beam 40 is not applied, but emission signals 41 are emitted from the sample 38 and received by the light receiver 48 in the same way.
The emission signal 41 emitted from the sample 38 is weak. Furthermore, according to the conventional apparatus 37, the amount of the emission signals that can be detected depends on a numerical aperture (NA) of the object lens 42, which means that only emission signals that emitted within the area of the object lens 42 can be detected. Therefore, most of the amount of the emission signals 41 is not detected, and the efficiency of detecting signals is not desirable.